Fix for script errors when unloading a SplitView
Fix for script errors when unloading a SplitView

Disconnects all signals from child items on destruction

Task-number: QTBUG-32526

Change-Id: Ib0b2e13be549164d4c967359856971c9d08d2a6f
Reviewed-by: Richard Moe Gustavsen <881e230b58d8abf8efbd9b8ce5a2db05f1d53614@digia.com>

drgvond/qtquickcontrols,kobolabs/qtquickcontrols,mizukusak/qtquickcontrols,mizukusak/qtquickcontrols,kobolabs/qtquickcontrols,drgvond/qtquickcontrols,kobolabs/qtquickcontrols,drgvond/qtquickcontrols,mizukusak/qtquickcontrols